Pressure sensor IC's are used in medical equipment such as in automatic high blood pressure meters. Consequently, pressure sensor ICs must meet stringent pressure test parameters, and the contamination to which pressure sensor ICs are exposed during manufacture must be strictly maintained.
An important test during the manufacture of pressure sensor ICs is a destructive over pressure test. In a conventional over pressure test, a pressure sensor IC, which has been singulated from a semiconductor wafer, and mounted and wire bonded to a substrate, is placed in a pressure chamber. The pressure in the pressure chamber is increased to an extreme pressure and maintained for a predetermined duration. If the pressure sensor IC remains intact for the predetermined, duration, the pressure sensor IC under test passes the over pressure test. Otherwise, the pressure sensor IC under test disintegrates and disperses fragments of the disintegrated pressure sensor IC within the test chamber, thus failing the over pressure test. A disadvantage of this method is, each pressure sensor IC must be singulated from a semiconductor wafer, and mounted and wire bonded to a substrate, before over it can be over pressure tested. Consequently, when a unit fails the over pressure test, the time, materials and equipment utilisation that were used in the singulating, mounting and wire bonding processes are wasted.
Hence, there is a need for a method and an apparatus for over pressure testing pressure sensor ICs prior to singulation from a semiconductor wafer.